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Lathe Boring 316 Stainless - Getting Chips to Break


May 21, 2020
For the low price, Korloys king drills are pretty great. Travers has 1.25" 3xD for $365, comes with a nice case and 2 boxes of inserts. 5xD is $507.
I use a smaller one in duplex often.

Sandvik had a nice sale on their newer DS drills in september but that's over now. Their old 880's are good too.
Don't worry about breaking a chip so long as the chips make it out of the hole its fine, around .0032" feed and good through coolant to get the chips out. I use a 880 .937" up to 4.5" deep in 316, Duplex, 625 Inconel, no problem at all. Insert life isn't too good in inconel but in stainless it'll drill all day long without changing edge.

I’ll try it with a 1.25“ 880 drill. Looks like 2044 and 1144 for inserts? Is that what you’ve been using in stainless? Thanks again for the help!


Jan 12, 2003
Those are the grades I use yeah, works good in stainless, duplex, inconel.
I was using my new DS20 1.312" going 6.2" deep in 316 a few days ago, 1150rpm and .0035 feed was about 64% on the Z thrust load of my Lynx2100LB, spindle was 38%. 145psi, more pressure would be nice bit this gets the chips out ok enough. now I'm debating getting a 1.75", looks like the machine can handle it.